A function commonly required in an automated article handling system is that of a buffer. More precisely, it is commonly necessary to provide a buffering function between two article handling operations which proceed at different paces.
In an automated integrated circuit handler, individual integrated circuits are output at a fairly constant rate. However, they are output into several different categories and the rate at which parts are output into each category varies. in addition, the ultimate output from the handler is not typically in individual parts, but in sleeves containing multiple parts. Therefore, a buffering function is required to accommodate the various output rates in the various output categories and to provide a sleeve filling capability which is triggered when any particular output category has sufficient integrated circuits therein.
In an automated integrated circuit handling apparatus, the primary concerns are throughout, direct labor costs and reliability. The effect of even minor improvements in throughput and the amount of manual labor involved in a final test operation, for instance, can be dramatic when compared with the total manufacturing cost of each integrated circuit.
In some cases, such as surface-mountable integrated circuits, a handling apparatus must also be designed to fastidiously avoid changing the position of the metal leads of the devices. When combined with the requirement of high throughput, or rapid movement of parts from one point to another, this places rather severe constraints on the design of a handler; and particularly on the design of a buffer apparatus.